My next questions after that will be what specific parts do you have already? You said you have a 03 cobra v8 so im assuming thats the cobra engine your going to swap. How complete is the engine does it have the supercharger and throttle body, exhuast headers? Do you have any other parts with it like intercooler, intercooler expansion tank etc? If your not sure of what you have pictures are worth a thousand words.

I beleave your v6 came factory with a T-45 if its a manual car. If so you can use a belhousing adapter and tranny cross member to bolt it to the cobra motor. However it wont be as strong as the T-56 the 03 cobra was made with and may need to be sent to a trans shop to be modified to take the extra horsepower and torque. If the v6 car is an automatic a good replacement would be a presure shifted automatic trans (not electronic) since the 03 cobra was never made with an automatic ECU. If your car has an automatic which I beleave is an AOD-E it will not work for the swap. I would suggest a C-4 or Turbo400 with a custom transmission adapter plate and custom tranny cross member for a pressure shifted auto trans if an auto is what you want. Also unless you go with the T-56 a custom driveshaft will be required. If you use a T-56 you will still have to aquire a custom or cobra tranny crossmember and driveshaft. For a cobra supercharger Ebay has been a good source for factory cobra superchargers in the past and still should be. If not many aftermarket replacements are available. And you will also need to consider how you are going to wire your tach as the v6-03cobra tachs are different. For this I would suggest keeping your stock tach and getting a separate boost gauge to mount inside or you could just run no boost gauge but its up to you. I will continue to answer questions as you have them.

Your radiator will need to be upgraded to the stock cobra unit or an aftermarket unit to support the extra horsepower. The 03 cobra was made with an IRS rear end but this was done by ford to help balance the engine. Your stock 4 link style 8.8 rear will work without any upgrading but you will need to use 3.55 gears to keep from using an aftermarket tuner with the 03 cobra ECU. Furthermore the 4link your v6 car has will give you better performance than the cobra IRS setup by about 2 tenths a second in the quarter mile just becasue its lighter and creates more traction. The 03 cobra engine block is also forged iron and weighs about the same as a 460 engine, this means you will need 03 cobra front springs to make the car driveable and I recomend using stock GT springs on the rear. Also to use your current manual trans you will need a custom tranny crossmember, a company called stifflers makes one that should fit your application. A custom driveshaft will need to be used as well. I recomend moser 33 spline axles for this application. And yes once the swap is properly completed you will be able to drive it like its a v-8 car as long as the engine and parts you use are good.

Ok sounds like a lot but I already put a lot of money on the appearance and I don't wanna sell it so umma just upgrade it to a v8. That's all the questions I have now but if I get more later ill just message u cuz u know ur mustang stuff thanks a lot

Your welcome. Also theres the exhuast. You will need to use a Cobra mid pipe and a GT catback, not a cobra catback. The cobra catback is designed around the cobra IRS which you will not have, a GT catback is the proper exhuast setup to use, stock or aftermarket as long as its for the GT. As well the cobra midpipe may be stock or aftermarket. And obviously Cobra air intake and cobra mass air will be needed but im guessing you already have that since you said you had what you needed to make it run.

I did a little looking around and it would seem I was wrong. I thought ford did away with the 7.5 rear end by 04 but they didnt. You will need a 8.8 rear end but I recomend one for a GT. Dont use the cobra IRS setup.